This program is designed to develop an on-line HPLC or FIA organohalogen photoelectroanalyzer. Many organohalogens have biological properties, including carcinogenesis, mutagenesis, and/or teratogenesis. New and improved methods of trace analysis for such compounds will assist the regulatory agencies, industry and federal and state governments. Use of such an analytical approach for organohalogens, especially one that is compound/analyte specific, sensitive at trace levels, and fully on-line and automated using relatively inexpensive and easy-to-operate instrumentation will save time and effort and enhance our ability to detect these compounds in environmental samples. This approach will use post-column, on-line, photolysis of the HPLC or FIA eluent to generate new photolytic species that have specific electrochemical detection properties. The generation of chloride form organochlorine compounds, bromide from organobromine, or iodide from organoiodine, will be detected as a function of the working electrode surface material, oxidative potential, and dual electrode response ratios. Compound identification would be based on: 1) chromatographic retention times and capacity factors; 2) qualitative lamp on and lamp off responses of compounds injected; and 3) dual electrode response ratios as a function of working electrode materials and potentials applied. The final HPLC/FIA-hv-EC approach will be selective for specific organohalogen compounds, and sensitive at the parts-per-billion level. It will provide minimum detection limits for the organohalogens far below those now possible by all other HPLC-detector approaches. The final instrument for trace organohalogen analysis will be applied to a wide variety of organic compounds in various sample matrices, such as: 1) environmental pollutants in air, water, soil, sediment, biological materials, etc.; 2) drugs found in animal or human samples; 3) industrial process streams, raw materials, intermediates, or finished products using organohalogens.